I've got a comparator whos inputs i wanted to protect from overvoltage, so I used a 5.0V TVS diode, but I'm getting all sorts of bizzare results.
First off, I'm powering the board off a 300mA transformer. There's a TVS diode between the +5 and GND lines, but it seems like it's sucking a lot more power -- I measure only .9V with the TVS diode in place, and
4.9V without the TVS diode.I've also used them on data lines, but it breaks the PWM communications when it's added.
I generated a 5V 50Hz square wave from a MCU and had the output line connect to a TVS (which was connected to ground). I didn't see any change in the output w/ and w/o the TVS on my scope. It seems like it's behaving as it's supposed to (letting 5v through), but in both the case where it's attached to the power line and where it's attached to the data line, it's causing grief.
The TVS diode I chose was the SMAJ5.0(C)A, which is supposed to be a bidirectional diode. They can't be installed backwards, can they? Any thoughts?
Thanks, Reza